RE: [sv-bc] packed union net ?

Ok.
I'm just wondering : why isn't it allowed with the same resolution method as
in user-defined net types ?

Regards,
Radek
  _____  

From: Bresticker, Shalom [mailto:shalom.bresticker@intel.com] 
Sent: Monday, October 13, 2014 2:48 PM
To: Radosław Nawrot; 'SV-BC'
Subject: RE: [sv-bc] packed union net ?



Thanks.

 

It was deliberate for wires not to be allowed 2-state built-in data types,
because such drivers can have multiple or no drivers, resulting in X or Z
states, which 2-state data types cannot express.

 

Regards,

Shalom

 

From: Radosław Nawrot [mailto:Radoslaw.Nawrot@aldec.com.pl] 
Sent: Monday, October 13, 2014 15:42
To: Bresticker, Shalom; 'SV-BC'
Subject: RE: [sv-bc] packed union net ?

 

BNF allow it :

net_declaration12 ::= // from A.2.1.3

net_type [ drive_strength | charge_strength ] [ vectored | scalared ]

data_type_or_implicit [ delay3 ] list_of_net_decl_assignments ;

 

data_type_or_implicit ::=

data_type

| implicit_data_type

 

data_type ::=

integer_vector_type [ signing ] { packed_dimension }

| integer_atom_type [ signing ]

| non_integer_type

| struct_union [ packed [ signing ] ] { struct_union_member {
struct_union_member } }

{ packed_dimension }13

| enum [ enum_base_type ] { enum_name_declaration { , enum_name_declaration
} }

{ packed_dimension }

| string

| chandle

| virtual [ interface ] interface_identifier [ parameter_value_assignment ]
[ . modport_identifier ]

| [ class_scope | package_scope ] type_identifier { packed_dimension }

| class_type

| event

| ps_covergroup_identifier

| type_reference14

 

Additionally  (As a workaround ) user can define own nettype:

 

6.6.7 (User-defined nettypes):

Certain restrictions apply to the data type of a net with a user-defined
nettype. A valid data type shall be

one of the following:

a) A 4-state integral type, including a packed array, packed structure or
union.

b) A 2-state integral type, including a packed array, packed structure or
union with 2-state data type

members.

 

BTW : Is it inconsequence that LRM allows 2-state user-defined nets but
disallows (according to 6.7.1 citatum ) 2-state build-in net ?

 

Radek

 

  _____  

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of
Bresticker, Shalom
Sent: Sunday, October 12, 2014 3:07 PM
To: 'SV-BC'
Subject: [sv-bc] packed union net ?

Can a net be a packed union ?

 

6.7.1 says,

 

Certain restrictions apply to the data type of a net. A valid data type for
a net shall be one of the following:

a) A 4-state integral type, including a packed array or packed structure.

b) A fixed-size unpacked array or unpacked structure, where each element has
a valid data type for a net.

 

However, 6.11.1 defines packed unions as integral types:

 

"The term integral is used throughout this standard to refer to the data
types that can represent a single basic

integer data type, packed array, packed structure, packed union, enum
variable, or time variable."

 

Thanks,

Shalom

 

Shalom Bresticker 
Communications & Storage Infrastructure Group Design Automation

Intel Jerusalem, Israel 
+972  2 589 6582 (office) 
+972 54 721 1033 (cell) 
http://www.linkedin.com/in/shalombresticker 

The devil is in the details.

 

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